Sorting apparatus



Feb. 23, 1954 R. F. STEHLIK SORTING APPARATUS 15 sheets-Sheet 1 Filed Aug. 4, 1948 A INVENTOR. RUDOLPH FRANK STEI'ILIK Feb. 23, 1954 R. F. STEHLIK 'SORTING APPARATUS 15 Sheets-Sheet 2 Filed Aug. 4, 1948 Feb. 23, 1954 R. F. STEHLIK 7 SORTING APPARATUS Filed Aug. 4, 1948 15 Sheets-Sheet 5 1954 R; F. STEHLIK SORTING APPARATUS l5 Sheets-Sheet 5 Filed Aug. 4, 1948 INVENTOR. RUDOLPH FRANK STEHLIK BY flififl w ATTY.

R. F. STEHLIK 2,670,087

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Feb. 23, 1954 R. F. STEHLIK SORTING APPARATUS 15 Sheets-Sheet 8 Filed Aug. 4, 1948 K 5 5 M, ZM N T m WM m m F M W a a mu 4 W o W W F R m M 8 i 1 o. m I 0 w @H w. M 4 d WHIQ m Feb. 23, 1954 s u 2,670,087

' SORTING APPARATUS Filed Aug. 4. 1948 15 Sheets-Sheet 9 1' 1 i l 1 /3/3 I 1 3 3 I 7 l I: I: l Z H61 L 190's do:

- IN ME N T01? Feb. 23, 1954 R. F. STEHLIK 2,670,037

SORTING APPARATUS Filed Aug. 4, 1948 15 Sheets-Sheet 10 an 3% IORA IIRARRA IRA ERA SKA SRA 6R8 M CA ' "H I goo?.

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SORTING APPARATUS Filed Aug. 4, 1948 l5 Sheets-Sheet 11 if c INVENTOI? 212 ZIZS RUDOLPH F/iF/VA 5724/11;

Feb. 23, 1954 R. F. STEHLIK 87 SORTING APPARATUS Filed Aug. 4, 1948 15 Sheets-Sheet l3 ans lans Feb. 23, 1954 $TEH| |K 2,670,087

SORTING APPARATUS Filed Aug. 4, 1948 15 Sheets-Sheet l4 Fla-3.21

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SORTING APPARATUS Filed Aug. 4. 1948 15 Sheets-Sheet 15 s42 -sss ea: FIGZZ F1623.

Patented Feb. 23, 1954 UNITED FSTATE' S' PATENT OFFICE y I 2,670,087 7 e SORTING APPARATUS Rudolph Frank Stehlik, Antwerp, Belgium, 35- signorto Automatic Electric Laboratories Inc.,

Chicago, 111., a corporation of Delaware Application August 4, 1948, Serial No. 42,419

. l The present invention relates to apparatus for sorting articles and is more particularly "con-' cerned with the sorting of small packages such as mail. I

The problem of relieving the burden of letter sorting has been given considerable attention and several machines, either entirely mechanical or part mechanical and part electrical. have been designed to eliminate to some extent the human element in letter sorting. It will be understood that asatisfactory solution of the problem is dimcult owing to the number of variables present and while the prior arrangements have provided cons'iderable relief, they do not attain the degree of improvement which is necessary and possible.

Generally speaking the layout of mail sorting apparatus is similar for diiierent types of apparatus and consists of a plurality of receptacles into which the mail is discharged. Above the top of the receptacles is arranged a platform on which the operators are seated and each operator is provided with a keyboard, operation of which controls a letter carrier so thatit discharges its contents into the appropriate receptacle. Usually the letter carriers are arranged to move at uni for-m speed past the operators positions and past the receptacles in a single continuous chain which introduces the disadvantage that the speed of operation of the operators is determined by the speed of movement of the letter carriers. A further disadvantage of the "prior arrangements resided in the fact that by their very nature it was essential to allocate particular letter carriers to particular operators positions. Thus, to obtain the maximum efiic-iency of the system. the operator must work at a given fixed speed and such working is not always easily realised since while one operator may have to deal with a succession cl correctly-andlegibly addressed letters, another operator may during the same period have to deal with some which are legibly-and others which are illegibly or incorrectly addressed and the speed'ofmovement of the letter carriers has to be acompromise between the two possible speeds of operation. Further, by requiring that one opera tor may only use particular ones of the letter carriers, the arrangement lacks the flexibility which a satisfactory arrangement should possess.

It is the main object of the present invention to-providean arrangement in which a complete independence of one operator from another of each operator from the speed of movement of the letter carriers is attained. Other objects of the invention are the introduction of a'number-of incorporated in letter sorting apparatus.-

16 Claims. (Cl. 214-11) In the present invention any number of operator positions may be provided. Stacks of unsorted articles are loaded into the apparatus. One by one, the articles are automatically fed to one of the operator positions where the operator reads the destination marked thereon and operates appropriate switches or keys of a control board located at each operator position. This routes the article to a particular one of a number of chutes or channels, each leading to a different moving :chain which carries a number of article carriers.

The article will be deposited on the first carrier to appear, unless this carrier is already loaded, in which case, the article will be held until an empty carrier appears. Should other articles be routed to the same chain of carriers by the same operator before the first article is deposited onto an empty carrier, the subsequent articles will be stored in separate reservoirs, to be deposited into empty carriers in the order in which the articles left the operator position, as empty carriers arrive at the reservoir.

Collection receptacles into which articles are to be finally deposited, are uniformly arranged about the machine in horizontal rows and vertical columns. All of the carriers "in one particular chainhave access to all of the receptacles in one particular horizontal row.

As an article is deposited onto a carrier from the storing reservoir, the carrier is given a code marking determined by the operator. All of the collection receptacles have permanent code markings. When, the moving carrier reaches a receptacle bearing a code marking which is in accord with the code marking on the carrier, the article is discharged from the carrier into the receptacle, under a positive driving "force.

The code marking on each receptacle consists of a simple strapping between particular pairs of electrical contacts. The code marking on the carriers is accomplished by setting variablypositioned conducting members provided on the carrier.

In one embodiment of the invention it is proposed to employ five letter carrying chains arranged to move in a substantially oval path. Each vertical column of letter receptacles will then comprise five receptacles and it is proposed to employ vertical columns giving a possible total of 360 receptacles. Six operators positions are arranged around the oval path of the carrier chains above the top of the receptacles which are also positioned around the oval path in six groups of 10.. It will'be understood that according to this embodiment of the invention all the receptacles need not represent different destinations but that corresponding receptacles in each group could be employed for frequently-occurring destinations with consequent economy in the use of the carriers since a carrier having a letter deposited therein at one operators position for such a destination would be emptied and available for use before it arrives at the next operators position.

The invention will be better understood from the following description of one embodiment taken in conjunction with the accompanying drawings comprising Figs. 1 to 23 in which:

Fig. 1 shows a front elevation of the whole equipment,

Fig. 2 shows a plan view of the whole equipment,

Fig. 3 shows the arrangements used for feeding the letters to a conveyor which carries the letters one-by-one in front of a sorters position,

Fig. 4 shows diagramatically the construction of one of the chutes into which the letters pass from the conveyor,

Fig. 5 shows the construction ofthe upper and lower portion of the chute,

Fig. 6 shows the construction of the discharge channel and one of the letter carriers,

Fig. 7 shows in greaterdetail the construction of the discharge channel of the letter carrier, Fig. 8 shows the general construction of the letter carrier,

Fig. 9 shows the arrangement for setting th letter carrier so that it will discharge the letter into the correct letter or destination receptacle,

Figs. 10, 11, 12 and 13 show the setting arrangements in greater detail,

Figs. 14 and 15 show the spring gate closure for the receptacles,

Fig. 16 shows the arrangements for indicating when a receptacle is full and Figs. 17-22 when arranged as shown in Fig. 23 are the electrical circuits for controlling the operation of the equipment.

The general arrangement of the equipment will be seen from Figs'l and 2 of which Fig. 1 shows a front elevation and Fig. 2 shows a plan view.- The equipment consists of a raised platform 100 with a number of operators positions 101 arranged symmetrically around a table 102. Each operators position has associated with it a conveyor 1113 which is fed from the series of rollers l 04 shown diagrammatically at the left-hand side of Fig. 2. The letters are transported to the equipment in boxes by means of a common conveyor 105 from which they are taken manually and deposited in feed arrangement 106 associated with each set of rollers 104, care bein taken to ensure that none of the feed arrangements are allowed to become empty. When a box is empty it is returned for refilling down the slide 101. Each individual conveyor terminates'just beyond the associated operators position in a chute 108 and the letters are directed along channels in the chutes in accordance with the operation of keys on a keyboard individual to each operator's position.

The destination or letter receptacles 109 are arranged in columns underneath the platform 100, corresponding receptacles in the columns being individual to a particular carrier chain. The front of the receptacles are closed by a door 118 shown only for one receptacle in Fig. 1, the door. being in the form of three prong hinged at the top. The electrical equipment is housed behind all fill

4 panels such as Hi (Fig. 1) while the receptacle H2 (Fig. 1) is the dead letter receptacle.

The arrangement for feeding the letters to an individual conveyor is shown in Fig. 3 and consists of two fixed parallel side walls of which one only, 56!, is shown and an inclined wall 592 making an anglof approximately 55 with the fixed wall, the'three walls and the base 5G3 forming a channel with a tapering end. A movable wall 504 works in slots 595 in the base 583 of the channel and is secured to bands 586 which are connected to spring-urged pulleys 501' to cause the movabl wall to exert a pressure on the letters whereby they are continuously urged against sets of rollers 1M. The rollers 104 are vertically arranged adjacent to the sloping wall 502 and are driven through the gearing shown in such a manner that the speed of rotation of the rollers increases in the direction of movement of the letter. Thus it will be understood that as the letters are urged forward by the movable wall 504, the letter in the front will be separated from the adjacent letter owing to the difference in speed of rotation of the rollers and hence the letters will be advanced one by one between the rollers and fed into the container 509. The container 509 has a movable base or trap 510 which is under the control of the magnet 511. The container is positioned above the conveyor which consists of a number of trays 512 suitably hingedtogether and passing over hexagonal driving members 513. The driving members 513 are mounted on shafts 51d and 515 of which 515 is driven by an electric motor (not shown in Fig.- 3). The conveyor is moved one step each time the operator keys up a destination and at the end of a step, the magnet 55 l is momentarily operated to move the trap 510 whereupon the letter in the container is discharged into the empty tray which has been positioned under the con tainer 509.

One pair 516 of the last set of rollers is car: ried by a pair of arms of which one, 511, only: is shown in Fig. 3. These arms are pivoted on a spindle 518 which is spring-controlled to move the pair of rollers 516 towards the other pair 519 of the set. The arm 51".? carries an operating member 526 which controls the spring contact pair 521 in such a manner that these contacts are closed by the operating member 520 whenever a letteris between the rollers 516 and 519. The contacts 521 control the opening of the circuit of the motor (not shown in Fig. 3) which drives the rollers through the shaft 522, the closing of the motor circuit being efiected when the operator keys up a destination. This operation will be explained in greater detail when the electrical control circuits of the equipment are-described.

The trays carrying the letters pass between walls 523, the front one of which is provided with a window 524 opposite to the associated operators position. Each step of the conveyor thus brings a letter to the window and the operator upon reading the address thereupon keys up the destination on the keyboard. The conveyor then makes a further step and the letter slides from the tray into the chute 108.

As an alternative to having the rollers 1B4 rotating at progressively increasing speeds, it would be suflicient if the rollers on one side of the letter were rotated at one constant speed the same order.

aevaos'z therrollerstheywould be separated during their travel between the rollers. The arrangement of the parts whereby a letter passes from the chute to the destination or letter receptacle is shown schematically in Fig. i. The chute W8 has a main portion 109 and a subsidiary portion lill, the letter passing to one or the other portion according to the position of an electromagnetically-operated vane 102. Dead letters are directed to the subsidiary portion and pass to the dead letter receptacle H2. The main portion of the chute is divided into five channels I03, 194, 185, Hit and 197, entry to which is controlled by vanes I98, 199, ll!) and 7H. Each channel is divided into three reservoirs 890,.89l and 802 controlled by vanes 803 and 805. Letters are fed to the reservoirs in the order 890, 80!, 892 and are fed from the storage reservoirs to a discharge .reservoir 9% in The latter isheld in thedischarge reservoir 909 until an available letter car.- rier 90! (Fig. 6) passes the discharge reservoir when the letter is released and passes into and is held in the letter carrier. The letter carriers are indicated in Fig. 4 by the two driving wheels M9, 920 resting on rails 92!, 922 and by plate 934 on which the letter rests. The letter is then transported in the carrier until it is adjacent the appropriate receptacle i599 when it is released and falls under gravity into the receptacle. The'construction of the chute IE8 is shown in greater detail in Fig. 5. The vane Hi2 which directs theletters into the main portion 19% or the subsidiary portion FM is controlled by the spring H2 to open the main portion 199 of the chute. The vane is operated to its other position to thereby close the main portion 790 and open the subsidiary portion 19! by an eleotroinagnet EF, the operation of which causes the armature and the associated linkage to pivot about the point H3. The vanes l98|l l which control the entry into the five channels mt-4B1 are similarly controlled by springs H4, H5, Hi5, "Ill and electromagnets BEV, 4EV, ZEV and IEV. In the normal position, all the electromagnets are dethree storage reservoirs 89%, 239i and 892 and entry into the reservoirs is controlled by the two vanes 863 and 804. As shown in the drawing, the vanes are in the position in which the first reservoir 809 is open and they are controlled. to openthe otherreservoirs jointly under the control of springs 8G5, 895 and links ear and 898 attached to the armatures'oi the electromagnets IER and ZER. respectively. A letter arriving with the vanes in this position wil1 fall into the storage reservoir see.- On the arrival of the next letter, the electromagnets lER are operated to close the reservoir 8% and to open the reservoir Bill 50 that the letter is deposited in the reservoir 80;. Finally, if no discharge has taken place by the time the third letter arrives, will be deposited in the reservoir 392. The method of operation of the clectromagnets will be described, in detail when considering the electrical controlgcircuits." 1

,-.The-letters pass from. the storage reservoirs to a discharge reservoir (not shown in Fig. 5) under the control of magnets iIET, 2E1 and SET which. control the traps 8&9, M0 and 8 closing the reservoirs, the magnets operating successively so that the letters are discharged down the plate M2 in the same order as that which they were received. The traps are controlled by links 813 Md and m5 attached to! the armatures of the electromagnets.

When .a letter is discharged from one of the storage reservoirs, it is held in a discharge "reservolr shown in detail in Fig. 6 and indicated generally therein by the reference 909. This discharge reservoir retains the letter by stop lever 9H3 until such time as an idle carrier such as 98! registers therewith. The discharge reservoir consists of a base 992 and two parallel side plates 903.. An arm till is pivoted at 908 to one of the lugs 9.04 and is connected by a spring to plate 982 while the side walls 9.93 are maintained in position by means of levers 999 and 91.9 pivoted thereto. These levers are pivoted to the mounting plate, the lever 9H) forming a stop for the letter. The lever 969 is forked, each fork bearing a roller 19!], one of which is normally positioned in a recess in a lever 9I2 which is pivoted to the lever 9I3 of a plunger type solenoid 914. The lever 9l3 also acts on the arm 9t? through the roller M5 and on the plate 992 through an aperture 946 in the plate 992 and is pivoted at sac. vIt .is normally biased to the posit-ion shown in the drawing by means of a spring 9!? so that on the energisation of the solenoid, the lever 913 rotates in a clockwise direction about the pivot 9 Hi.

The letter is discharged from the discharge reservoir into the letter carrier upon the energisation of the solenoid 9 which takes place when .an available letter carrier is adjacent to the discharge reservoir. The energisation of the solenoid causes the clockwise rotation about piv- 0t 9.16 of the lever Hi3 which efiects the following operations (Fig. 6). During the first stage of the rotation, the arm 98'! is rotated clockwise about the pivot Silt until it engages with the letter resting on the plate i162, the letter being henceforth held down between the plate and the arm. Further rotation of the lever '9l3 now causes the plate 9E2 and, of course, the arm .99! to be moved downwardly towards the letter carrier, the plate being guided in the slots 906. As will be subsequently described, the letter is gripped between rollers on the carrier and drawn into the carrier. Also, during the initial movement of the lever Sit, the lever 98 2 will move substantially in the direction of its own length to cause clockwise rotation of the lever 999 whereby the side walls 2W3 are lowered below the plate 8E2, the right-hand roller 9 being with- I drawn from the recess so that both rollers now ride on the underside of the lever 9l2' to prevent the side walls rising until the return to normal of the armature. This lowering of the side walls is necessary since the carrier is continuously moving so that there is bound to be some .sideways movement of the letter during transfer. The lowering of the walls also causes clockwise rotation of the stop lever em to allow passage of the letter to the carrier.

The letter carrier as: consists of a frame 9l8 (Fig. 6) provided with wheels $19 and 928 running on rails 313i and 922 respectively. -At present, the carrier will be described only as re-- gards themechanism for'withdrawing a letter from the discharge reservoir. This mechanism.

as better seen'in Fig. 7, comprises an electromagnet 923 secured to the frame 9I8 and having an armature 924, an extension 925 of which is pivoted to a mounting 926 which is itself pivoted at 93I to the framework and carries the roller 927. An arm 928 is pivoted also at 93I and carries an operating member 929 for controlling the contact springs 939 and also a roller 932, the roller 932 being urged toward the plate 935 by a suitable means such as a spring (not shown). The roller 921 is adapted to engage with a roller 933 on energisation of the magnet 923, the latter roller being driven from a suit- "able. source of power as described subsequently.

When the electromagnet is energised, the armature extension 925 causes the mounting 929 to move counterclockwise about the pivot 93I so as to cause the roller 921 to move towards and engage the roller 939. The energisation of the electromagnet is arranged to take place slightly after that of the solenoid 914 so that the letter is moving towards the carrier by the time the electromagnet is energised. When the letter passes under the roller 932, the letter forces the roller 932 away from plate 935 causing arm 928 to rotate about pin 93I in a clockwise direction which in turn causes contacts 939 to close due to the movement of member 929. These contacts complete a circuit to cause the roller 933 to be driven in a clockwise direction in a manner hereinafter described. The letter, which has now been positioned between the rollers 933 and 921 by the discharge reservoir mechanism, is seized by the rollers and moved into the letter carrier.

When the letter has passed the roller 932, the

latter passes through a slot 934 in the plate 935 to cause anti-clockwise rotation of the arm 92!? whereupon contacts 939 open. The opening of contacts 939, as described later, disconnects the drive from the roller 933, so that the letter is held between the rollers 92! and 933 and in the position in which the rear end has just passed the roller 932. It will thus be understood that with this arrangement each letter, irrespective of its size, will be held in the carrier in such a manner that when it is to be discharged into the appropriate destination receptacle, a small movement only is necessary and the extent of the movement is substantially the same for all letters. The discharge of the letter into the destination receptacle is controlled electrically in a manner to be described later, but the effect as regards the mechanical equipment is to cause the roller 933 to be again connected to the source of power for a pre-determined period sufiicient to feed the letter into the receptacle.

The carrier also carries four electrically conducting rollers 936, 931, 938 and 939 which engage conducting strips 949, 94I, 942 and 943 inset into an insulating base 944 secured to the rail 922. Two of these conducting strips are continuous along the carrier track while two consist of short lengths located adjacent the chute at an operators position. The rollers serve to complete circuits between the electrical equipment on the carrier and the electrical equipment associated with the operators positions.

-I'he carrier is also provided with an arm 945 having arrangements which, under the control of a group of magnets provided at each operators position, are set to characterize a particular destination receptacle as determined by the operation of the appropriate keys by the operator.

These arrangements will be described in detail subsequently.

The general construction of the letter carrier is shown in Figs. 8 and 9 and it should be explained at this stage that all the carriers in a particular chain are driven by an electric motor mounted on one of the carriers in place of the usual rollers and other mechanism. Adjacent carriers are connected together so that the single motor drives the whole chain. The motors are of the variable speed type to enable the speed of travel of the chains to be varied as previously mentioned. The mechanical drive to the rollers 933 on the remaining carriers is taken from the lefthand one of the rollers 929 by means of continuously-meshing bevel wheels H99 and HM. A plunger-type solenoid H92 is provided on each carrier and the plunger H93 which is coaxial with the spindle I I94 of the bevel I I9] is provided with a clutch plate I i95 which, when the solenoid is energised, engages with a similar plate H99 on the rear of the bevel II9I. Movement is then transmitted from the bevel I l9I through the spur wheels H97 and H98 to the driven roller 933. In

' addition to the solenoid I I92 and the electromagnet 923, the carrier also carries two relays H99 and H i9, the operation of which will be described when considering the electrical control of the equipment.

Referring now to Fig. 9, this shows the mounting arrangements for the rails on which the carriers run and also the positional relation between the carrier chains. An arm indicated generally by I299 projects from the main frame (not shown) of the equipment and carries the top rail 92i for one carrier chain and the bottom rail 922A for the carrier chain above so that the carrier chains are mounted one above the other. A further arm I29I secured to the main frame is arranged parallel with the arm 945 on the carriers and is provided with 12 conducting strips i292 arranged in recesses on an insulating'base I293 for use in connection with the setting mechanism. The setting magnets IM to I2M are also indicated and are suitably secured, by means not shown, to the arm I299. Five groups of magnets, one for each carrier chain, are provided at eac operators position.

A detailed description will now be given of the setting arrangements with particular reference to Figs. 19 to 13. Mounted on the arm 9 35 are four substantially triangular shaped plates I399 arranged to pivot about the points I39i. Each plate is provided with an upturned edge I392 on each longer side, a gap between the two edges being provided at the apex. The armatures I393 of each of the magnets 1M to I2M are provided with extensions I394 at the free end of which are secured operating members I399 each having a roller I395 at its end. In the de-energised condition of the magnets, the rollers I396 take up a position such that they are clear of the plates I399 as the carrier passes the particular operators position. When a magnet is energised, its associated roller may or may not engage with the walls of the plate according to the position last taken up by the plate. For instance, as shown in Fig. 11, the magnet 2M has been operated to indicate that the plate must take up the central position. Since the plate is already in this position, the operation of the magnet is without effect on the plate. The same is true of magnets 5M and HM. The magnet (M is also operated thereby indicating that the corresponding plate should take up the left-hand position (the posi-- memos? tion in which the plate .isshown on the drawing), and this is efiected by engagementof the :roller with one oi the side walls of the plate. It will be understood that, when the same carrier is again controlled by the magnet at another operatofs position, this plate'will be reset to the appropriate position as determined by the. operation of the magnet.

Each of the plates $3M is associated with a carriageleol mounted on the underside of the arm 945 on the samespindle- Iillit as the associated plate so that the plate and; carriage move together. The free end of. the carriage is pro videdrwith a. spindle lace- .on which aresmounte'd the bracket i309 (below the carriage) and the yoke I316. (above the. carriage). The bracket I309 carriesa roller I31 I adapted to engage with any one of three of the conducting strips IZM,

straps I.3I2 being pivoted to the yoke 3.45 and the arm 965 so that the roller 43. retains its alignment with the conducting strips. .I 202. as the plate and carriage are rotated. The three positions which may be taken up by a plate are defined. by spring-pressed balls I313 located in recesses. in the arm M5, each of which balls engage with one oi three depressions. I314 in the carriage Ilfll. The spring-pressed balls also allow for the upward movement of the carriage as the roller passes over the insulating well bebeen the conducting strips. Two of the plates are. set to characterize the tens digit ofa destination receptacle and the other two are set to characterize the units'digit and it will be seen that the three possible'position-s of the" plates willgive all numbers from 1 to-99.

As the letters are discharged from'the carriers. they fall into destination receptacles which as previously mentioned are arranged in fivelevels. As shown in 16, the letters as they enter the destination receptaclesrest on a flap IBMlsecurecl to the spindle 19d! pivoted in the base of .the receptacle W32. The fla mac is provided with an extension. 195:3 which operates on. the sprin controlled rod 19% which carries at its free end a flag I 9.65 bearing an, arrow. Normally this flag is behind the-mask 1906. but whenthe weight of the letters reaches a certain value indicatingxthat the receptacle is becoming fullthe flag I905 proiects to give a visual indication of this "factas shown in the-drawing.

:The receptacles are closed by a three-pronged grid-H (Figs. 14 and 15:), the top of which vis secured to a bracket lBIlI having a right-angle extension I892. The bracket is mountedon the spindle 1853 which pivots inthe fixed mounting 4684. A coiled spring I 805 is provided between the fixed mounting and the; extension m2. so that the grid is normally in the closed position. All that isv necessary therefore to remove the let.-

ters is tor the collector to insert his fingers be.- I

tween the three, prongs of the grid and withdraw the letters by pressing back. the prong-s, the prongs immediately snapping back tothe. position shown in. Fig. 15.

The electrical. circuits. of. the equipment are shown in detail in Figs. l'l to 22., which should be arranged as shown in Fig. 23. These circuits include the arrangements for selecting a particular chain or level; the register .or relay set on which the'tens and units digits are registered; the circuits for controlling the movement of the conveyor; the circuits for-controlling the carrier to discharge the letter'into the appropriate destination receptacle and finally the-circuits of the electromagnets for controllingthe operation of 10 the vanes in the chute. leading to the carrier.

As previously mentioned, the operator is provided with three sets of keys, oi. whichone set A to E- (Fig. 18) is-employed for selecting the level,- a second set IT to 8'1 (Fig. 19) is employed for registering the tens digit of the required destination receptacle and the third set til to all is employed for the units digit. In addition, there is a key F which is operated in. the case of illegible or incorrectly addressed envelopes and which serves to direct the'letter into .a dead letter receptacle as previously mentioned.

The register equipment associated with each of the keys A to E comprises three relay groups BSA, RS3 and RS0 so that .therewill be a total of I5 relay groups. for each operators position Each of these registers corresponds to one of the storage reservoirs 8030,. 802 (Fig.5) while a fourth register RSD (Fig. 21'), which is provided on the basis of one for each level, has transferred to it the. tens and. units digits. when a letter passes from one of the storage reservoirs to the discharge reservoir. When an idle carrier is available, the indications stored on the fourth register are transferred to the carrier as markings by the. operation of the magnets lM to IZM previously mentioned.

The three relay sets REA, RSB and. RS0 provided for each key or level are 21.1rangedv to be allocated for use in turn .by means of a distributor switch iDS. A second distributor ZDS is employed to transfer the registrations from any .one of the registers RSA, RSB or RSC to the'fourth register RSD.

The circuits of the equipment located :on the carrier are shown in Fig. 22, where the relays i'CH'and ZCI-l correspond to relays IMO and I I shown in Fig. '8 while the solenoid 30H corresponds to the solenoid HM shown in Figtnand the magnet 4CH corresponds to the magnet 923 shown in Figs. 6 and .7. The'four rollers. @3643! are also shown together with the four strips flfl (Fig. 21), MI, 942 (Figs. 21 and 22') 963- (Fig. 221) with which the rollers engage. The strips 940 and-943 are. shorter than 9 and 942, engagemerit between the two latter strips and the rollers serving to feed battery and ground potential to the equipment on the carrier.

A detailed description will now be given of th'emethod of operation and for this purpose it-will be assumed that the: operator-has read the address on the. last letter behind the glass in the conveyor and has determined that itiis toga todestination receptacle 3'! in the bottom level of receptacles and that the level .key A and the tens key 3 and units key I have been operated- The operation of level key A closes alcircuit for relay lV (Fig. '18): and the opera.- tion of this relay serves to associate the tens and units lceys with .a pro-selected one of the registers RSA, RSB and RSC.

Thus, assuming that. the register RSA has been preselected i. e. there is no letter in the storage reservoir M0,. relay 'lV at its lower armature extends ground over the left-hand outer armature of relay G, wiper IDSI- on contact I, winding vof relay :IR to. battery. Relay I'R- in .operatingextends :the leads: MOB-4H1 from theztens and units keysuthrough cable 2.11M to relay, :tRAuto 'IxZRA of the relay set BSA and also closes :the circuit to magnet IER which: operates. to open storage reservoir 800. In addition, .ciV :at its inner upper armaturecompletes a circuit for magnet IEV which controls thczoperaation of the vanes'ltfl, HI to direct the letter fronr the chute 

